Eurasian Watermilfoil also known as Myriophyllum spicatum L. is a submersed, aquatic perennial in the Haloragaceae family that roots to the bottom of water bodies. The roots are slender and fragile. Stems emerge from root crowns, are smooth and hairless, and grow up to 21 feet to the water surface, where they branch profusely. Stems have layers of specialized, partially lignified cells that enable the stem to self-fragment without mechanical disturbance. Stem fragments are capable of forming new plants.
Eurasian watermilfoil can be found on every continent except Antarctica. It is native to Europe, Asia, and northern Africa. It colonizes rivers, lakes, and other water bodies. It grows under a range of trophic conditions, but it is considered an indicator of eutrophic (low levels of dissolved oxygen, high levels of organic matter) conditions. Growth and spread is limited by light, wave action, temperature and depth, preventing colonization of deep waters or water with high suspended particles. Optimum water depth for growth ranges from 3 to 13 feet, and a maximum depth for growth is 39 feet. It can tolerate moving water, and water currents and wave action facilitate fragmentation and colonization to stiller waters.
Once established in an aquatic habitat, Eurasian watermilfoil grows rapidly in spring (March-April). Stolons, lower stems, root crowns, and roots persist over the winter in California. In waters where temperatures do not drop below 50 degrees F. (10 degrees C.) there is little seasonal die-back. Root crowns store starch that fuels early takeover of the water column. During the growing season this plant undergoes auto-fragmentation, with fragments often developing roots before separation from the parent plant. Sloughing of plant parts is common after flowering.
While the present invention will be primarily described with respect to Eurasian Watermilfoil (Milfoil) it will be understood by those skilled in the art, that the invention also has applications to other invasive weed species. Aquatic invasive weeds are nonindigenous species that threaten the diversity or abundance of native species, the ecological stability of infested waters, and/or any commercial, agricultural, aquacultural, or recreational activities dependent on such waters. (As defined by the Nonindigenous Aquatic Nuisance Prevention and Control Act of 1990). Aquatic invasive weeds are introduced plants that have adapted to living in, on, or next to water, and that can grow either submerged or partially submerged in water. There are hundreds of aquatic invasive weeds that have infested U.S. waters such as the European Water Chestnut (scientific name Trapa natans, or T. natans) which is another invasive aquatic plant released inadvertently into waters of the Northeast in the late 1800s, that is slowly but inexorably spreading throughout the Northeast where it is in clogging waterways, lakes and ponds and altering aquatic habitats.
Aquatic invasive weeds, such as Eurasian Watermilfoil, have been introduced into lakes and other waterways by aquariums, remnants on boats, boat trailers and by other accidental means. They are fast growing and can easily spread rapidly and engulf an entire area. Early attempts to remove this invasive weed were by mechanical means (i.e. cutting). This proved to be unacceptable because they can easily multiply by stem fragmentation and root runners can simply grow into new infestations, exponentially complicating the problem. It has proven to be difficult to collect all the fragmented pieces and prevent/control new infestations. Listed below is a non inclusive list of aquatic invasive weeds.
Alligator weed (Alternanthera philoxeroides)
Brazilian Waterweed (Egeria densa)
Caulerpa Mediterranean Clone (Caulerpa taxifolia)
Common Reed (Phragmites australis)
Curly Pondweed (Potamogeton crispus)
Didymo (Didymosphenia geminata)
Eurasian Watermilfoil (Myriophyllum spicatum)
Giant Reed (Arundo donax)
Giant Salvinia (Salvinia molesta)
Hydrilla (Hydrilla verticillata)
Melaleuca (Melaleuca quinquenervia)
Purple Loosestrife (Lythrum salicaria)
Water Chestnut (Trapa natans)
Water Hyacinth (Eichhornia crassipes)
Water Lettuce (Pistia stratiotes)
Water Spinach (Ipomoea aquatica)
This is not a list of all invasive aquatic weeds, nor does it have any regulatory implications. The list is provided as an informational tool and for patent purposes to indicate the different varieties of aquatic invasive weeds that this array can treat. Extensive laboratory and field testing has been completed with Milfoil, Curly pondweed and Coontail weed varieties.
Numerous sources describe the importance of keeping aquatic invasive species out of lakes. However, there is little information on how to exterminate the problem without the use of herbicides or mechanical means. Extreme infestations have even less options. Below is a summary of the current control methods used by entities with aquatic invasive weeds problems:
1. Public awareness
2. Manage boats and trailers that may spread aquatic weeds from other bodies of water.
3. Mechanized cutting and pulling weeds
4. Manually cutting and pulling weeds
5. Commit to an intensive monitoring program
6. Covering with mats for long periods of time
7. Herbicides (not commonly allowed in most water bodies without special permissions and a rigorous permit process)
Frequently aquatic invasive weeds, specifically milfoil infestations occur in the shallow areas near docks and piers. These areas usually have warmer still water with more nutrient rich water that encourages weed growth. The water depth in these areas typically ranges from 8 to 15 feet.
Milfoil, is a herbaceous aquatic plant that is becoming more well known. The stems grow to the water surface and can form dense mats on the water surface. The primary means of spreading is from small rhizomes and fragmented stems. These small fragments can easily break off the delicate plants. When these fragments sink to the sediment layer they re-root and grow. This is the primary way the weeds spread and cause infestations.